1. Field of the Invention
This invention relates to an apparatus for making a fiber lap from chemical fibers, cotton or the like. The fiber lap is utilized, as a more or less coherent mass, as the input material for further fiber processing such as carding, cleaning and the like. The lap forming apparatus is of the type which includes a fiber opening device having a fiber feeding device at its input and a series of rotating sawtooth rolls and a depositing channel in which the fiber material thrown by the last sawtooth roll is deposited on a continuously moving, fiber-supporting surface which is air-pervious and is exposed to suction for causing the fiber tufts to temporarily adhere thereon.
2. Background Information
In a known apparatus of the above-outlined type such as disclosed, for example, in German Patent No. 3,522,208, an endless circulating screening belt is, as a fiber receiving surface, positioned underneath a plurality of sawtooth rolls (carding cylinders). The sawtooth rolls throw the fiber material tangentially downwardly onto the upper surface of the travelling screen belt. The air needed for the conveying air stream between adjoining sawtooth rolls is drawn in between the sawtooth rolls from supply air channels arranged above the bight of the rolls. In this manner, with each sawtooth roll there is associated a downwardly oriented suction stream.
It is a disadvantage of the known prior art construction in that it is technologically complex, and that the individual sawtooth rolls discharge the fiber material onto the screen belt at different flow rates.